Aflatoxicosis in fingerling common carp (Cyprinus carpio) and protective effect of rosemary and thyme powder: Growth performance and digestive status

Abstract

Dietary aflatoxin B1 contamination is a demanding challenge for aquaculture industry. The present study was conducted to elucidate the effect of dietary aflatoxin B1 contamination on growth and digestive status of juvenile common carp. The effect of dietary inclusion of rosemary and thyme to prevent such effects was also investigated. Fingerlings were subjected to seven treatments including various dietary aflatoxin B1 contamination (0, 50, 100, 200, 300 and 400 ppb) and a group received diet contained 400 ppb aflatoxin B1 and 4% rosemary and thyme powder. The experiment lasted for 12 weeks. Results revealed that dietary aflatoxin B1 contamination did not affect growth performance. However, intestinal alkaline protease, lipase and amylase activity of fish were increased according to aflatoxin B1 diet levels. In addition, intestine tissue lesions including necrosis, immune cell infiltration and fibroplasia were manifested with increasing dietary aflatoxin B1 content. Digestive enzymes activity was ameliorated by dietary incorporation of the plant powder in those fish received diet with 400 ppb aflatoxin B1, but it did not prevent intestinal lesions. In conclusion, juvenile common carp showed no changes regarding various growth indices even at 400 ppb aflatoxin B1 level. Although, 50 ppb dietary aflatoxin B1 did not significantly affect growth or digestive enzymes activity of juveniles, it caused mild intestinal tissue deteriorative changes. Including the medicinal powder blend in diet with 400 ppb aflatoxin B1 could ameliorate the increased digestive enzymes activity; however, it did not prevent the intestinal tissue pathological changes. Understanding the exact mechanisms behind such protective effect requires further studies.